Method and apparatus for cold milling soap and other materials



. 9, 1952 D. E. MARSHALL ET AL METHOD AND APPARATUS FOR COLD MILLING SOAP AND OTHER MATERIALS 6 Sheets-Sheet l Filed July 15, 1950V D. E. MARSHALL ET AL METHOD AND APPARATUS FOR COLD MILLING SOAP AND OTHER MATERIALS Dec. 9, 1952 6 Sheets-Sheet 2 Filed July l5, 1950 D. E. MARSHALL ET AL METHOD AND APPARATUS FOR COLD MILLING Dec. 9, 1952 SOAP AND OTHER MATERIALS 6 Sheets-Sheet 3 Filed July 15 1950 SN S Q .MW

7am/d E. Marsha/f .Ja/'m A Harrmgfan Egbert L- frana Dec. 9, 1952 D. E. MARSHALL r-:T A1.

METHOD AND APPARATUS FOR com MILLING SOAP AND OTHER MATERIALS 6 Sheets-Sheet 4 Filed July 15, 1950 17ans/d E Marsha/'l .Ja/m A. Herring tan I I l l x x l l,

D. E. MARSHALL x-:TAL 2,620,511 METHOD AND APPARATUS EOE COLD MILLING SOAP ANO OTHER MATERIALS Dec. 9, 1952 Filed July l5 1950 6 Sheets-Sheet 5 Dec. 9, 1952 D. E. MARSHALL ET AL 2,620,511

METHOD ANO APPARATUS ROR COLO MILLING SOAR ANO OTHER MATERIALS Filed July 15, 195o e sheets-sheet e 7e (ISV/ 'fq. Z0.

Patented Dec. 9, 1952 *UNIT-'ED STATES 2,620,511 PATENT ()F FICE Illinois Application July 19502,' Serial No. 4174,084y

34 'Claims'.

This invention .relates to milling methods and vapparatus and refersinore lparticularly to the cold4 milling. of soap'.` The copen'ding applica# .tion of Donald E..Marsha-l=lf, Serial'. No. 129,942, led November 29, 1949', dealt with the original'` `system in which la. high speed carrier-band is :passed through'a closely tted milling or con'- version channel.. The present invention deals with severalV modications. of this earlier system which provide'- n'ew degrees offeectiveness, new 'functions and'.` generally -extends .the application of. the system into wider. fields as well as.- increasing vthe-"capacity of the systemY for certain materials.

As" in .the 'aforesaid copending. application, the purpose of this invention isto renne the'physical propertiesv vof cold. milled .soap fby' subjecting the-:soap in' its"'solid.state' toy shearing. and vcompactin-gl forces' of. an rentirely'.unprecedented intensity and to fd'of :so without developing destructive heating:` ofv .the fmass undergoing. treatlasfzan '.ultra-micrccrystalline state, is. thezkey to high viscosity; .butln'o' 'one' heretofore; .has ever achieved .these high. viscosities by .milling alone inw-a` manner compatible with-.'comrnercialisoap production.

Ifn 1941 .Russian .experimenters vpurportedly converted; unadulterated milled' soap so as.' to show .traces o'f. itransparency andi. .thus possess the desired...small.V particle size`.by repeated-.cold

rollerrmilhn'g. (about ve times that given `to method of millingby which ythe unadulterated soap ranging in moisture content from ve percent (5%) to seventeen. percent (117%) in the solidstate isv subjected to an extremely fastacting and powerful Ashearing and compacting. force for but for a brief instant so thatfthedesi-red. ne particle subdivision and compa-ating is obtained Without appreciable heating of the soap; Also aeration and dispersion of the air in the soap Amay be -a-ccomplisl'iedv during this high speed action 'without requiring. a closed system.

Stated broadly, -themethod by which this iinvention achieves-- its purpose involves first forming theY soap into -a/ nlm-like sheet andthen quickly acting upon the sheet by means of a band travelling at high speedv and contacting one side of the sheet tomove'thesurface layer at said `side of the sheety .relative tcthe surface layer at the opposite side-of thesheet atalspeed sufficiently .great so `that'inertia eiec'ts ne .subdividing and compacting of Vparticles throughout th-e mass of material'compris'ing vthe sheet.

The apparatus for `carrying out thisimethod comprises relatively movable complementary milling members fha-ving vclosely adjacent milling surfaces `[of substantial area defining" therebetween a shearing and compa-cting zonefthrough which. the soap material to vbemilled passes at relatively high l'speedasa film-like sheetand in its passage' through .said zone has extremely hi'gh'ispeedfmotion .imparted lto" the surface layer at. one side thereof'zrelative ItoV itsl otherV surface layer, and crosswise so'f thedirecton in which thefsheet passes through the shearing: and -Lcom'-l pacting zone;

In. its preferred. form. thev apparatus makes use of. the high `speed 'shearing effect of' anfendlesvsjL band trained-:abouti a. .pair of .pulleys one or both. of which varel'driven'ai'rhigh speed',.raiid which drive the ban-d through an extremely narrow'rnillin-g slo't or oriii'ee through whi'chftne material to be milled' isforce fed', crosswisei'of the band, and brought -into shearing contact withA bothA sides of the band; Not onlJyxi-'gv the band employedA to shear 'and compactthasbali but it is also used to carry sufilcierit`ai`i1,ia`dher ing as a iilin tolthesurfaces of'tliebar'id, into the vmilling orice for vaeration o'f thefsoap 'if desired., Congestion and aeration grooves -in the walls of t-he milling orice-may'ibef provided to cause occlusion and dispersion1 inthe-soap of the airbrought into the mllngorilce'loythe high sp'eediban'd.

As' 'will appear "more" fully hereinafterg, this manner of effecting' shearngand `com'pactirig has ay very"important advantage frointhes'tandpoint `of` dissipation of the heat Ageneratjed'in theprocess; `The 4extreme high Yspeed 'at whichl the shearing Vaction `takes Yplace yminir'i'iizes' the 3 amount of heat produced, and that heat which is generated -is carried away by the band and/or the walls of the Inilling orifice before it can have any ldestructive effect upon the material.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the unique method and apparatus substantially as hereinafter described, and more particularly -dened by the appended claims, it being understood that such changes in the precise embodiment of the hereinafter disclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate several examples of the physical embodiments of the invention constructed in accordance with the best modes so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a side elevational view of a band converter embodying the principles of this invention;

Figure 2 is a plan View of the apparatus shown in Figure 1;

Figure 3 is an enlarged longitudinal sectional view taken through Figure 2 along the plane of the line 3 3 and illustrating the manner in which the material to be milled is fed through and removed from the milling zone;

Figure 4 is a perspective View diagrammatically illustrating the manner in which milling is accomplished;

Figure 5 is a cross sectional view taken through Figure 1 along line 5 5;

Figure 6 is a cross sectional view taken through Figure 1 along line 6 6;

Figure 7 is an enlargement of a portion of Figure 5 showing slightly modified details of the parts in the milling zone;

Figure 8 is a greatly enlarged sectional View taken through Figure 3 along the plane of the line 8 8 and showing the congestion andv aerating grooves in the sides of the stationary milling members;

Figure 9 is a, diagrammatic View showing the grooved configuration on the surfaces of both stationary milling members thrown open and with the milling band edgewise therebetween;

Figure 10 is a View showing a pair of knives acting on the milling band to scrape soap from the sides thereof after leaving the milling zone;

Figure 11 is a view similar to Figure 3 illustrating a modied form of feeder for forcing material to be milled through the milling zone;

Figure 12 is a cross sectional view through Figure 11 taken along the plane of the line I2-l2;

Figure 13 is a detail sectional view taken through Figure 11 along the plane of the line Figure 14 is a side view of the flake produced by the conversion of soap by the apparatus of this invention;

Figure 15 is a view of the opposite side of the ake shown in Figure 14;

Figure 16 is an enlarged cross sectional view on the order of Figure 7 but showing the use of ungrooved milling surfaces on the stationary milling elements;

Figure 1'7 is a fragmentary perspective view of the milling elements seen in Figure 16 but showing the same separated;

Figure 18 is a View of a modified milling band;

Figure 19 is a view partly in side elevation and partly in section illustrating a rotary milling apparatus embodying the principles of this in- Vention;

Figure 19a is a fragmentary sectional View showing a modified version of the rotary type mill shown in Figure 19;

Figure 20 is a View partly in side elevation and partly in section showing a special viscosity testing apparatus; and

Figure 21 is an enlarged sectional View of a portion of the apparatus seen in Figure 20.

In general the method of this invention comprises forming the soap material to be milled into an extremely thin sheet or lm of between .O01 and .015 of an inch in thickness. This sheet is force fed edgewise through a slit-like extrusion orice and while it passes therethrough motion is imparted to the surface layer at one side of the sheet relative to the surface layer of material at the opposite side of the sheet at a speed high enough to eifect subdividing and compacting of particles throughout the mass of the material comprising the sheet.

In this method it is essential that the feed and the relative motion between the surface layers of the sheets be at a rate suiciently high to usefully employ the churning of the mass of the material comprising the sheet for the subdivision and compacting of particles in the mass of the material, and to also avoid temperature rise in the mass to or beyond the crystalline reversion temperature.

In exploring the nature of soap investigators have determined that soap is a two phase system, that is, that it has a hard crystalline phase and a soft more soluble liquid crystalline phase which together determine the soap structure. It has also been determined that important qualities are imparted to soaps by the conversion of the crystalline nature of this material. Physical alterations of its structure are known to achieve large transformations in such qualities of the soap as hardness, lathering, elimination of soapdish jelly, swelling and welding without any other changes in the chemical formula, in th fats used, or in the moisture content.

The apparatus of this invention employs a high speed endless milling band to achieve these large transformations in the hardness, lathering, swelling and Welding characteristics of soap solely by alteration of the physical structure of the soap effected by subjecting it to the high speed shearing and compacting action of the milling band.

Heretofore, the conversion of the physical characteristics of soaps has been limited to a few basic processes, one of which is taught in the Bodman Patent No. 2,205,539. In this process, the structure of soap is altered physically while the soap is in a semi-fluid State, but the process requires that the moisture content of the soap being Worked be between fifteen percent ,(15%) and twenty percent (20%) and the temperature approximately F. to maintain the semi-fluid condition of the soap.

Another basic process in widespread use at the present time is known as the cold milling method. In this process soap chips in a solidified state are fed between rollers Which produce a limited degree of subdivision and compacting of the particles in the mass of the soap. The roller milling process, however, can only be carried out when the soap to be milled is in a certain highly critical state of plasticity which enables it to adhere to the rollers and thus feed properly through the bite of the rollers. This requires that the soap contain at least twelve percent (12%) tov fourteen percent (14%) moisture.

The roller milling process is also characterized by a slow crushing and shearing action on the soap, in which the pressure on the soap is great but the rate of its application relatively slow. In contrast, the apparatus of this invention, which may be termed a high speed band converter, makes use of much more intense and extremely fast acting forces for the-shearing and compacting of particles in the mass ofthe soap, thereby minimi-zing the exposure time of the soap in the milling process necessary to produce the desired particle subdivision andcompacti-ng. rPhe refinement of soap is carried to a newl high level by the method and apparatus of this i-nvention, since through it extremely fine milling of Asoap may be accomplished on soaps of far lower moisture content than is possible onrollcr milling equipment, with the result that it isnow possible to produce either aerated ordeaerated low moisture converted barsoaps in the ultramicrocrystalline phase with the particles of the soap compacted to a very high degree.

In the past the employment of high shearing speeds has been discouraged because of such obstacles as the amount and rate of heat which theywould cause to be generated in the soap to be milled; the limited ability-to remove this heat and avoidcrystalline reversion; the mechanical vdifficulties in maintaining close milling clearances;A andthe extremely low capacity of close vclearance milling.

Withthe high speed band milling apparatus of this invention, however, it is now possible to produce ultra milled soap which will give longer lasting service because of its greatly increased viscosity, which willv be less wasteful in use, and which will be free of cracks due to swelling during use.

Heretofore soapwas prevented fromv developing cracks during use only if the soap material was homogenized in a semi-fluid state during the process of making the same, and this inturn required the presence of adulterating moisture as a "plasticizen Heretofore, neither the beta soapl made in vaccordance withthe teachings of the Mills-Patent No. 2,295,594, nor soap of the type made in Aaccordance with Bodman No. 21,310,931, nor hard cold milled soaps had the advantages which result vfrom the ultra renement of soap/by'l the method andapparatus of this invention.

Referring now more particularly to the accompanying drawings, which illustrate several types of apparatus embodying the principles of this invention, Figures 1 to 10, inclusive, show the preferred form of the apparatus. As here shown the apparatus comprises a frame I8 having an Velongated horizontal bed and upright portions II at the opposite ends thereof, each deflninga -housing containing a large diameter pulley I-3. These pulleys are supported by the frame for rotation on vertical axes adjacent to the ends of the frame with their peripheries in vhorizontal alignment with one another. One, or both, of the'pulleys is adapted tombe rotated at high speedby means of V belts I4 trained over sheaves I5-on the pulley shafts I and connect- 4ing with a driving pulley, not shown.

-A flat endless band- I1 is tra-ined over thepe- -nipheries of the pulleys I3 to be drivenv at high Yspeed thereby, and as will appear hereinafter, this band comprises the high speed milling member of the apparatus.

Encircling one straight horizontall stretch of the band I1, andextending for substantially the faces on the blocks.

entire distance between the upright `portions .lli of theframe, is an assembly of parts which jointly denes a nozzle-like feed chamber iiabo-vethe band and open along its bottom, a milling zone I9, at opposite sides of the band, in open communication with the feed chamber and in which shearing and compacting of the soap or other material fed therethrough from the feed chamber is effected, and a receiving `chamber 20 vbeneath the band.

This Aassembly isr carried byl a pai-r of opposite angle shaped members 2I extending between and fixed to the upright portions I I of the frame and which together define a substantially channel shaped bridge with the flanges 22 and 23 of the channel extending upwardly. The horizontal legs 2li of the angle shaped members, which de.- ne the back or web of the channel, are at. a level slightly beneath the lower edge of the band I1 and their adjacent ends are lspaced yslightly from opposite sides of the plane of the band to denne the entrance into the tubular receiving chamber 2U. The latter, of course, is supported from the undersides of the legs 24 of the. angle shaped. members.

Seated on the upper faces of the legs-254` of the angle shaped members 2l and at opposite sides of the band I1 is a pair of stationary milling elements or blocks 2t and 21 havingflat milling surfaces v2a directly opposite the iiatfsidesof'the band I1 and spaced a very slight distance therefrom. Hence, it will be seen that the surfacesvi'2f8 of the stationary milling members and the opposite sides of the band I1 define a milling, or shearing and compacting izone, through which soap or other material in the feed chamber ISIS may be forced to effect exceedingly fine milling of thematenial as it passes through the clearance spaces at opposite sides of the milling band.

Viewed in another manner the entire space between the surfaces 23 on the stationary milling members may be considered a slit-like orifice having a relatively short dimension crosswise of the band. Since the band I1f travels through the central 4portion of the space between the sta.- ticnary milling surfaces 28, there are actually a pair of these slit-like orifices, one at each side of the band.

The feed chamber I3 is mountedl on the top of the milling blocks 26 and 21 and is substantially tubular in cross section. It is made in complementary longitudinal sections, however, detachably secured together as by bolts Sil atthe joint along the upper marginal edgesof the members and other bolts 3I which pass downwardly through flanges on the lower edges of the sections to secure them to themillingblocks. In this manner the millingr blocks are-confined between the underside of the feed chamber and the horizontal iianges of the angle-like supporting members 2 I.

Referring to Figure 5 it will be noted that the milling block 21 is iixed with respect toits supporting member 2I andthe section of the feed chamber seated thereon, while the other block 26 is slidable horizontally at right anglesr to the adjacent flat side of the milling band and guided for such motion by dovetail connections 3,3 with the upstanding flange 23 of its angle-like support 2|.

Consequently the block 26 can be moved toward and froml the adjacent side of the milling band to decrease or increase the transverse dimension of the space between the milling sur- Such adjustment may be 7 readily effected by loosening the screws 3l which thread into the block 2@ and bodily shifting the same as by means of an adjusting screw 34 threaded through the fiange 23 and connected with the block.

Attention is directed to the fact that the complementary sections comprising the feed chamber I8 have hollow side walls to define passages 35 through which water or any other suitable coolant may be circulated to remove heat from the walls dening the sides of the milling orifice and the material moving through the milling zone as well.

Again referring to Figure it will be noted that the inner opposing sides of the milling blocks 26 and 27 diverge outwardly and upwardly from points just beneath the top edge of the milling band to define a substantially funnel shaped entrance to the milling zone above the surfaces 28 on the blocks.

It will also be seen that material passing downwardly from the feed chamber into the funnel shaped entrance of the milling zone is constrained to fiow to opposite sides of a separator 36 extending the full horizontal length of the slit-like milling orifice and disposed edgewise in line therewith. The lower portion of this separator is disposed closely adjacent to the entrance to the milling orifice but is slightly spaced from the sloping side walls of the milling blocks so that the material passing downwardly between the blocks is metered and divided by the separator and formed into sheets before entering the milling orifice itself. Screws at the opposite ends of the separator mount the same in position at the inlet of the milling orifice, and these screws preferably provide for a degree of adjustment of the separator toward and from the mouth of the milling orice so as to achieve the desired metering effect.

Both milling blocks and 2l preferably have hollow interiors dening passages 3l through which water cr any other suitable coolant may be circulated; and the separator likewise has passages 38 through which a cooling medium' may be circulated.

Referring for convenience to the Figure l diagram, soap or other material to be milled is fed under pressure into the spaces in the milling orifice at opposite sides of the band l ll, and while in a thin sheet it is forced downwardly through the milling zone crosswise of the milling band. While pa-ssing through the milling zone, these sheets are subjected to intense shearing and compacting forces exerted thereon by the opposite sides of the high speed milling band I?, so that exceedingly fine subdivision and compacting of the particles in the mass of the material is accomplished.

The time the material is in the milling zone and the length of travel through the zone are regulatable and dependent upon the `pressure of feed together with the speed of the band.

The material thus milled drops into the bottom of the receiving chamber 2) and is delivered therefrom by means of a screw conveyor liti in its interior driven by a chain di connecting with a drive sprocket, not shown. It is sufficient to note that the conveyer carries the milled material horizontally in the direction of travel of the high speed milling band toward a large discharge opening "i2 from which the milled soap may drop into any suitable container placed therebeneath.

At its top, or feed side, the milling zone will be full of material to be milled during operation of the apparatus, and hence closed to the atmosphere. However, the bottom or discharge side of the milling zone communicates with the interior of the receiving chamber 2i) which can be kept open to the atmosphere by driving the screwl 4i) at a fast enough rate to prevent accumulation of milled material in the receiving chamber.

If desired, however, the discharge side of the milling zone may also be kept under pressure, and for this purpose a slide 43 mounted on the discharge end of the receiving chamber and having a restricted orifice 44 therein may be slid into place across the opening 42 of the chamber 20 to restrict the discharge of material from the chamber and thus allow the milled material to accumulate therein and to be acted upon by the screw 4U which will keep pressure upon the material at a magnitude determined by the size of the restricted orifice 44 and the rate of rotation of the screw.

The feed chamber I 8 is supplied with soap or other material to be milled by means of a more or less conventional plodder :i5 mounted on the left hand upright portion H of the frame in line with the feed chamber. The plodder, of course, is provided with the customary screw 46 which is adapted to be driven by a pulley 41 connected by a belt (not shown) with a drive pulley (not shown). The plodder feeds horizontally into the feed chamber, and because of the relatively great length of the latter, its cross section preferably decreases uniformly toward the end thereof remote from the plodder. Hence, uniform pressure will be maintained upon the material at the inlet of the milling zone along the entire horizontal length of said zone.

Another way of accomplishing the same result, but by which greater feed pressures can be obtained, is shown in Figures 11, l2 and 13. These figures illustrate a slightly modified form of feed chamber having an extension 46 of the plodder screw therein. The cross section of the extension 46 and the pitch of the threads thereon mayA increase progressively toward the end of the feed chamber remote from the plodder so as to maintain uniform feed rate and pressure along the entire outlet side of the feed chamber.

In this case also soap or other material to be milled is formed into film-like sheets before entering the milling spaces at opposite sides of the milling band. For this purpose, the feed chamber itself is provided with elongated slitlike passages 49 at either side of a separator 3B formed as part of the feed chamber structure.

As best shown in Figures 3 and 10, soap or other material adhering to the sides of the high speed milling band may be removed before the band emerges from between the milling blocks by knives 50. The edges of these knives in contact with the sides of the milling band, however, preferably extend diagonally across the band as shown best in Figure 3.

As will hereinafter appear in greater detail, the size of the space between the milling band and the surfaces 28 on the milling blocks is one of the important factors governing the effectiveness of the milling operation. Because of the need for some adjustment of the size of this space, it may be desirable to have the surfaces 28 formed on readily detachable strips 52 extending along the entire inner sides `of the blocks. Thus, the strips 52 may be detached 9?.' andreplaced vvbyl other: similar:strips...ofa slightly less or. greater. thickness; depending'. upon the sizexof the `space-wanted.

Also, as will. appearinngreater-detail, here,- inafter, the surfaces 28 on; the. opposing side Walls of the milling. blocks; may'. either.. be grooved asv at. 54; orqtheyV may: be smooth. as seenat 55 in-Figuresl and 17'. Whenggrooves are used, they are` relatively' closely spacedbut haveless width thantheiat .lands556 between them. Also these grooves extend diagonally with respect to the milling bandA sothat the material entering the milling; zone will not only flow; downwardly but will/be directed` in` the direction of travel of the band tosome extent whileit is beingL subjecteditofrintense shearing and compacting forcesby thepband.

The grooves 54 maybe termed congestion and aerating grooves since they augment-:the shearing and compacting action of the high speed milling band and also make possible occlusion and fine dispersion of air; in the` soap being milled. This air is introduced Vinto the milling zone as athin film adhering by, molecular forces to the sidesy of the-milling band.

On the other hand when the sidesof the mill-v ingY orifice are smooth asV shown at 55 in Figv ures-l and 17, a minimum of aeration of the soaporother material being milled takes place,

and the resulting productisusually deaerated.

From the description thus far,4 it will be seen that the apparatus has-several outstanding features which enable it tov exert far more intense shearing and compacting forces on .the soap or other material beingmilled than-was hither to possible. These features are that each side of the movable milling; member or high speed band acts on and imparts high speedv motion to thel surface .layerv of. the.. iilrnelike.. sheet of soap, of between .001 and .015 of aninch Vin thickness, vwith Which it contacts; the-.fact that the milling band is adapted to travel through the milling zone at speeds ranging between 2,000 and 10,000 feet per minute; and the fact that at such speeds of travel the band is able to subject the soap or other material being milled tor forces which result almost completely in shearing, subdividing and: compacting-` of'. the particles vin Athe mass .of soap. .without uselessly churningthe soap. and. thus.-incurringv the pos-.- sibility of destructivey temperature rise-1 therein.

Offvery great importance; also is the fact .that soap or" other1 material tow be milled is-force fed. under..` pressure-on .theorder of` fifty (50) pounds persquare. inch-or higher, orosswiseof the: band ytravel and through themilling, zone; so.;as'to almost completelyl unburden the high speed; milling band of all that Work'which is related to the feeding function or the.vtrans portingof the soap into ancltthrough-the4 appa-ratus'\-withI the'result that greater' shear in tensityand consequently. highly efficient conversion is achieved,

The force feeding' of solid soap-or.' other material to be milled through the milling zone under substantial pressure is in itself a novel innovation in milling apparatus-of thev type herein question. Hitherto; for` example in-one-- form of rotating device,` namely'conventional `cold roller milling apparatus, the feeding of soap of high viscosity was accomplished entirelyby'theiadi hesion of soap to thesurface of thev rollers-and hence the soap was more or less impositively conducted through the biteof the rollers. More.- over, vthis type of apparatus'does: not' lend' itself totfpressuref feeding: ofi the.. soap throughzthe milling :zone rfoivthe.reasongthat :the .pressure of thezsoap against thefsurfaces of .therollersxwould exertA af terrific braking f effect.` thereonfresulting in high lossofvv power; .and ,thedifficulty, which would be encountered inithe provision. of. 1 a.y run--A ningseal around-'the-peripheri'es of thefeeder to constrainxthe-i scapytogpassagei through their bite. Sucht seal-s: also-'would-fexert` .afbraking' effeet .or-drag orr-thefrollers which together with the=drag=of the Asoap material' on'thefface of the rollerswould make `it impossible to control the temperature caused by drag orrobtain-.either effcient operation-of theapparatus orspeedsgreat enough to producefefcient shearingand. oompacting4 of 'particles in ythe-:masa of the-material being milled.

Also all roller mill's.` are: limitedatoshearing zones with. no appreciable'width because-ofi the line contact betweentwo articulating cylinders: This .limitation Carr-only.`` be met :byusing a; .pro hibitive numberl-of-'rollersto. accomplishu fine particleA refinement.'A

An: analysis.;y of z alli. other formsf of rotating milling apparatus; such asnther rim of; a. .spoke driven wheel orsimpeller operatingfwithinalsuri rounding casing. that carries the stationary milling members. or. 1. disc types vsuch .as'the' common attritionzmilhoperatingfwith. asingle disc against aistationaryV casing or: with two.l discs running in opposition; to" each' other,;. or; two elongated articulated y; worrnf impellers.: of small diameter operating within a., pressure. retaining casing, will reveal thatithepowerilosszdue tofeed pressures on" the ,mil-ling.: elements bythe fed material itself or by'itlefrunningVY seals usedv to coniine thev materiallto itszpathithe milling zones, .will become. major limitationsznot onlyon the eliciency ofthe processbut.4 moreimportantly on the intensity-to which the process can be care ried without reaching a: point' where the -heat generated. by 1 these lossess can.. no :longer be.: re.- moved. and` becomes,` destructive to thev material being refined'.

In the apparatus of"tlfiisainvention,v however; the straight l line travel. of fthe. high speed .milling band lengthwise through af slitdike-millingchane nel or oriicefinvolvesfthe use of aseal embracing only the cross: sectional arearofV the relatively thin .,milling:A band', at I the.- opposite: ends of l the millingchanrtlel.' In: the .present case the seals may bef-in' the nature `of "a labyrinth of '1 grooves-in the opposing walls of the milling blocks atta-rela tively short area .58 thereof r'where thefb'and enters the millingfzone; andzsimilar'fspa'ced.:sealing areas-'59 of somewhatcshorter"dimensionsatpthe opposite: end-V of they` milling. zone and; between which.` the :knives 150: are: situated:

By reason of .the fact vthat soapin a-solicl highly viscous state? approaches fone edge: oftheffband and vpasses throughthe millingzone :crosswisefof the band; equal pressure'dseXerted:upon opposite sides of the band Ytozhold it :centered inthe milling orifice; This edgewise .approach offeed 1 to the band also. minimizes-:the dragror braking effect of the soapv on theiband.' Since .themilling band is drivenv atxa .very"high-speed'y and the soap is travelling at fatsubstantial ratecrosswiseof the band through the milling zone, the inertiagofgthe mass of material comprising the sheets in the milling zone is usefully employed to eliminate the possibility ofV uselessy churningvof. the soap mass and. to greatlyzenhancefthe shearing and compacting :actionofithe band..

With the apparatus :-ofi'this-';invention, exceedingly ne subdivision and compacting of particles in the mass of the soap or other material milled is accomplished without raising the temperature of the soap to either the melting point orto vthe crystalline reversion temperature, primarily because of the exceedingly high speed at which the milling band i7 is driven and the short time the material is in contact with the band.

Theoretically, soap in a solid state formed into a film-like sheet .O inch in thickness can have one side thereof acted upon by the side of a high speed shearing and milling band to produce v subdivision of particles in the mass of soap in a surface layer that would be as little as one micron in thickness. This can be done without heating the remainder of the sheet provided the same is moved out of shearing contact with the high speed milling band before the band is allowed to dig any deeper into the sheet and also providing the action of the band does not produce any appreciable degree of distortion in the mass comprising the remainder of the sheet. Whatever exceedingly small amount of heat that may result from particle subdivision and compacting in this theoretical one micron layer will pass largely into the metallic high speed milling band rather than into the soap which is a much poorer conductor of heat than the band.

In actual practice, however, the shearing and compacting action of the high speed milling band goes much deeper into the sheet of soap passing through the milling zone (probably to 30 microns) than the theoretical one micron surface layer and also some churning of the soap comprising the sheet does occur. However, there are two kinds of churning, the slow and easy churning characteristic of conventional roller milling apparatus, and the fast and highly intensied churning produced in the soap by the apparatus of this invention. Such violent churning also produces'particle subdivision and compacting in the mass of a sheet of soap which is only approximately .005 of an inch in thickness; and thus there is no serious waste of power or destructive amount of heat generated in the soap being milled in the apparatus of this invention as long as the proper clearance is maintained at opposite sides of the high speed milling band, feed pressure on the soap and the rate of travel of the soap across the milling Zone is properly adjusted, andthe proper design of congestion groove is selected for each type of material to be milled. Y

Essentially ve variable factors must be manipulated in the high speed band converter of this invention: (1) The pressure required to feed the soap through the milling Zone; (2) the clearance in the shearing and compacting zone, or more particularly the space between the milling surfaces on the stationary milling elements and the adjacent sides of the high speed milling band; (3) the rate of travel of the high speed milling band; (4) the width of the shearing and compacting zone, measured in the direction in which the soap travels therethrough; and (5) the length of the shearing and compacting Zone measured in the direction of band traveltherethrough. The following is a discussion of each of these ve factors:

Feed pressure to the feed pressure. In other words the soap is caused to flow faster through the milling Zone as the feed pressure is increased. At present, feed pressures of approximately seventy ('70) pounds havebeen used satisfactory on tests conducted with the apparatus, but much higher pressures can be used. v

An important feature of this mechanical arrangement is the accommodation of extremely high pressures by the labyrinth seals and the ability to entrain a molecular layer of gas into such high pressure zones without it being wiped off the entraining member.

While higher feed pressures result in higher capacities of the apparatus without necessarily overloading the shearing capacity of the milling or conversion zone, these higher pressures also result in better cooling since the soap has less opportunity to absorb heat generated in the milling zone and exposure to the cooled walls of the stationary milling members is better.

Clearance The size of the space or clearance between the milling surface on each'of the stationary milling members and the adjacent side of the high speed milling band determines the thickness of each sheet of soap to be acted upon by the milling band, and can be from .001 to about .015 inch. In general the less the clearance" the more useful work goes into particle shearing and compacting and less useless work into churning at a rate insufcient to produce shearing of the particles in the mass of the soap.

With smaller clearances both the band and the fluid cooled stationary milling members are better able to remove heat from the milling zone.

Also with smaller clearances, the band may be of less width (edge to edge) so long as the band still has suflicient width that all particles in the material passing across it will be acted upon and sheared by the band; but this, of course, has the effect cf lowering the capacity of the apparatus for any given feed pressure and length of milling zone.

Band speed The milling band must always be driven at a speed which takes advantage of the inertiaI of the mass Vof the sheet acted upon so that the combined forces of the band and inertia on the mass of soap comprising the sheet cause high speed motion to be imparted to the surface layer of the sheet contacted by the band relative to the surface layer at the opposite side of the sheet. In addition the speed of the band must be vhigh enough so that any churning of the mass of soap between said surface layers will also be at a rate great enough to accomplish subdivision and compacting of particles in the mass of soap comprising the sheet.

The faster the band is driven the more intense becomes the shearing and compacting (but not in direct proportion to speed) of particles in the mass of material acted upon by the band, and the less useless churning in the mass. Conversion of the physical characteristics of soap by line subdivision and compacting of the particles in the mass of the soap requires a band speed of at least about 1,000 feet per minute, and a filmlike sheet of soap acted upon by the band measuring approximately .005 inch in thickness. At band speeds over 1,000 feet per minute shearing of the soap sheet and particles in the mass thereof occurs in a Zone nearest the band regardless of how far the band may be spaced from the Surface of the adjacent stationary milling mem- 13 b'er; and-fthe high speed churning of .thel mass forcefully fed through themillingV zonealso accomplishes shearingand vcompacting of lparticles bychurning-action aloneand bythe fact that such churningjfpresents new particlesto the band'from the' depth of the sheet.

In general the band should'4 be driven at a; rate approximatelyl 6 to 18-.times faster than the rate at ywhich vsoap isforce'fedthrough the milling zone;

If the band is to be driven at extremely high speedsx-it is possible that the -width of. thcqband (measured from edge to edge thereof) may be made lesswithout sacrificingtheeiiiciency; of the-shearingand'compactingaction. With higher band speeds; ,there is. also more tendency'l for heating to take place in the-milling zone, but this Iieatistaken away both'by the `band andby the walls :ofithe fluid.v cooledfstationary .milling meme b'ers.

Although. the f' bandi. may r4heat upY during*A the milling: process, thesoapl travels; across it and through'. the' milling' zone s at such" at a: rate; of speedfzthat it is'iincontactwith the band. only for aniextremelyl brief time, and hence' it'is'incapable of absorbing any appreciable heat from the-f band.

Th'ewdth of the milling zone SinceV the degree of Y con-version' of` the' soap sought -seems :to require reduction ofi thesize of thefparticles inthe mass of'soap toapproximately 1/2;y micro-n,r theoretically therefore, thereV isroom for 250 'of these .l/zmicron particles `in the.4 optimum spaceorr clearance,. betweeny .one side of the milling.- band and' the surfaceof the' adjacent stationary- Amilling element, of .005 -of .an inch'. Hence,it becomes clear that* axminimum width is that at which all particles in the mass of mate; rial being-,milled .are reached.

It also appears that the; most intense" 'shearing in .an sheet of soapvof 'this' thicknesszis' throughouta-zone of onlyr l()` tox25rmicronsy in:extent 'next tovthef; band; However; tests: have shown that thefchurning: produced: inf thef. sheet. of soap. is atia: enough rate; to". eiect shearinga. and compacting of particles in the mass of material I4 use ia.' band4 .widervv than .2 inches under 'the stated conditions seems to achievelittle-orno further conversion'.y

When high speed milling 'bands kWider than 2 inches are used, lower band speedscanbeV ein-- ployed fora given degree of conversion. Certain effects of a high degree of conversion, .such as transparency of the finished product, .may iinvolve `alignment of' particles in the massofzsoap milled as Well as particle subdividingv and compacting. Where transparency in soap is.-sought, band speed and clearance arepreferablyA adjusted to` achieve conversion of -the soap, and the viscosity of the converted soap is measured. The viscosity of the soap can then be considered a guide as to the minimum' conversion of the soap required. Thereafter the speed of 4the bandxmayfbe lowered and the width of the-band increased? with. the:v result' that better transparency Yofthefsoapfmay.l be achieved at any; given degree of conversion..

In special applications of this process to ho= mogenization without necessarily. reachingf particle subdivision, awider'band is used (such as 12 tof14 inches).. These widthsrequireicareful attention to congestion groove'idesign sof: as. to evenly spread the thin` layer` of materialbeing treated all over th'erwider. band.

LengthY Thelength of the millingslotiorzone, measured in the direction, of .band travel therethrough, has no proportionaleiect upon the. degree of; conversion of the. soap,v butit isobvious that the capacity of the vapparatusis.directly proportional to thelength of this zone.

The following. table, based upon .test runs` on soap of the standardized formula ofapproxi.: n'lately 15%, CNO. and. 85% tallow,.and at a moisture corrected to.'7%, deiines thespecial'ef'.- fects of each variable discussed above except length of the milling slot or zone (in. thedirection of band travel), .which hasv a directly proportional eiect on capacity. Therefore, mille ing-V rate isexpressedin poundsfper hour per inch of lengthof the-.milling zone` TABLE:

T-St., Clearance, vliessure, Shear, Width, Rate, Temp., Convcre in. lbsL/sq. in: ftlmin; 1u: lbs. Out.- sion Index 1 .002v 50 1,000l 1 20' 100 70 .002 70. 1, 000v 1. 25 105. 72

.005 70 3,' ODU 2 50 135 90 Aeration comprisingthesheet extending nearly allthrough the,..005`. of an inch. of.V its .thickness V due tothe fedf pressure, andbetter shearingv results .with the..use'oftlrecongestion grooves inthe surfaces on v.the stationary millingi members.

Tests" indicate that 'a 1 inchwide `band travel# 1ingat3,000 feet'per minutewill convert'soap well' beyond the degree l* possible with-v convene tional-cold roller milling apparatus; whileeay 2 inch-band'travellin-g at thefsame-speed will eiect much greaterconversionl and produce' cold milled scalzi'` of' an unprecedented highv viscosity. To

compacted milling zone as a thin molecular film which tenaciously adheres to the sides of the band. Such air is brought into contact with the adjacent surface of the sheet of soap passing through the milling zone and is occluded and finely dispersed in the soap by the joint action of the high speed milling band and the enveloping action on the material in the congestion and aerating grooves 54 in the sides of the milling slot or orifice.

These grooves not only assist the band in producing intensied churning in the mass of soap passing through the milling zone and thus augment the shearing and compacting action of the band, but also envelope the air introduced into the soap mass. Since the air brought into the milling zone .by the band is entirely occluded and dispersed in the mass of soap by speed and inertia While the soap passes through the milling zone, it is unnecessary to make the milling Zone air-tight to obtain a thoroughly aerated material.

Aeration can also be facilitated to some extent by effecting shreading of the soap immediately prior to entry thereof into the clearance spaces between the sides of the milling band and the surfaces of the stationary milling elements adjacent thereto. This can be accomplished as shown in Figures ll, 12 and 13 by a series of tooth-like obstructions 62 extending transversely across the passages 49 at opposite sides of the separator 36 and spaced from one another along the length of the separator adjacent to the bottom'thereof. These obstructions, and the milling blocks themselves, may be formed integrally with the sections of the feed chamber, as seen best in Figure 12.

As stated the obstructions 62 cause shreading of the soap just prior to its entry into the milling zone so that the soap brought into contact with the opposite sides of the milling band just outside the entrance to the milling Zone is in a better condition to envelope the air brought into the milling zone by the band.

When the apparatus is operated with smooth surfaces on the stationary milling members the air brought into the milling zone by the high speed milling :band seems to .be driven out over the lower edge of the band and lost if the receiving chamber is open,

Aside from their aerating function the congestion grooves 54 cause churning of the soap passing through the milling zone to such an extent as to prevent by-pass of the soap through the milling zone via the grooves, or without all portions in `the mass of the soap being subjected to the shearing and compacting effect of the high -speed milling band. Examination of the aerated flakes (either converted soap or synthetic detergent) discharging from the milling zone, see Figures 14 and 15, show that the akes have spaced ribs on one side thereof produced by the congestion grooves with the material in these ribs aerated to the same degree as the thinner areas of the flakes between the ribs. Also these thinner areas between the ribs show fine surface marks or lines which extend in the direction of band travel at one side of the flake and similar but less distinct lines at the opposite ribbed side of the flake which are substantially crosswise thereto, These marks or lines evidence the effects of violent tearing action on the soap passing through the milling zone when the apparatus is operating properly. This unique texture,

in iiakes packaged for laundry use, provides a degree of solubility and a .guard against matting on the clothes which is important.

While the converted soap product of the method and apparatus of this invention preferably is a thin flake having between iive percent (5%) and seventeen percent (17%) moisture content, it will be appreciated that materials of lower than five percent (5%) moisture content can be milled as well. With soap of such lower moisture contents, the milled soap will be in a powdered state, rather than flake form. l

It will also be understood that bar soaps can easily be made from these flakes by feeding them into a plodder and extruding in a more or less conventional manner. A plodder especially suited for handling aerated flakes without deaeration of the resulting product forms the subject matter of the copending application of Donald Marshall, Serial No. 177,268, led August 2, 1950.

Synthetic flakes made in accordance with this invention may be made into bars by first pulverizing the flakes and thereafter subjecting the pulverized material to aerated compacting such as in the copending application of Donald E. Marshall, Serial No. 129,093, filed November 23, 1949. Y

The band converter process of this invention produces soap having the following desirable and highly useful properties:

A. The highest viscosity for a given soap formula that has ever been produced while preserving the lathering qualities oi beta phase soap.

B. Non-swelling type of gel. It seems that the intensity of shearing and compacting achieved in the process is suiiicient to produce the most closely knit particle structure known Without the use of adulterants so as to give a flnished bar with good lathering qualities and yet long lasting texture.

C. Cold welding properties which are unique for milled low moisture, unadulterated soaps.

D. The highest lathering coefficient for soap in bar form because of the combined advantages of beta phase crystals and low moisture together with a shearing and compacting hardness which permits the use of the more soluble fats in the formula.

E. High resistance to deaeration, enabling integration of aerated flakes or chips in a conventional plodder and extrusion without squeezing the air from the akes, thus yielding a, well-knit soap even at moistures from twelve percent (12%) down to five percent (5%) and with a JE rystalline structure favoring the lathering qualiies.

F'. The best light transmission for unadulterated soaps having a particular value in giving a transparent jacket or finish to the bar.

If desired, the high speed milling band may have a slightly roughened surface indicated in Figure 18. As herein shown both sides of the band are given an extremely fine file-like surface 64 which may be defined by very slight scratches on the sides of the band at an angle of 45 to its long dimension, or substantially at right angles to the congestion and aerating grooves in the surfaces of the stationary milling elements. Such a band is capable of developing higher tearing forces on the soap, and these higher forces may be quite useful, when milling other materials such as wheat flour or the like. When using the band of Figure 18, the stripping knives should be set at such a diagonal angle with respect to the band that their edges are 17 disposed at rightangles to the lines or scratches on the sidesl of the band.

While onejofthe rmost'important uses of the apparatus described is the conversion of the physical properties of soap, its use is by no means limited to the refinement of soap. It may be used also for the refining of chocolate, margarine, paint and many other materials of similar nature as Well as for grinding and dehydrating during grinding of powdered or particulated material. For this latter use, the feed chamber and plodder may be removedand a-feed ,means for conducting the material through the lmillin-g zone entrained in a carrier gas such as air employed in place thereof. band-converted and aerated material yields an extraordinary uniformityand neness of grind.

When applied to4 dehydratinggrinding operations the band may beheated with a direct flame to carry heatin between the sheared fllms of material as well asusing the-.jacketed milling elements as steam heated surfaces-'for .driving off vapors. New degrees ofgrindingreduction are accomplished because .the material as it becomes extremely fine will still encounter shearing con- A ditions at these high speeds and close clearances.

Abrasive materials .such as the buildersi'used with soaps or synthetic detergents can be subdivided more successfully by this process because of good temperature control and the minimized abrasion of milling elements. The material is ground up on surfaces formed by .thematerial itself.

Particle neness and particle nearness within the mass of a pulverized piece of material is not to be confused with the sieveV test of` the pulverized material and it is important to'beable to preserve this conversion during grinding by the use of the present invention.

Synthetic detergents and their builders which are usually very hard salt crystals, particularly present a milling problem due to the erosion of the machinery on the milling elements. Such erosion seriously darkens and otherwise contaminates the detergent. To avoid milling; these synthetic materials have been molded from powders at extremely high pressures.; suiicient to Vmill the crystals and in that way refine the bars texture to some degree. However,in re-solidifying'when the pressure is removed these crystals do reform g.

and the bar inevitably has a sandy texture which lAlso, the recycling of once is objectionable in fine toilet soap merchandising.

The process for converting these materials into high quality bars calls for either superne grinding and aerated powder. com'pacting such ras taught in the copending application o f Donald E. Marshall, Serial No. 129,093, ledNovember 23, 1949; or conversion by shear and compacting of particles in mass, according to the present invention, at temperatures below the crystalline reversion point and with adequate aeration to lessen the extreme densityA of these materials in respect to soap.

The 'present process has Vfeatures for reducing the abrasion of milling members to a minimum. The shear is accomplished essentially by speed in place of pressure and-thisshear is largely between two surfaces of` theV material itself. The shearing band and channel walls can be considered as expendable andV cheaply replaced. The aeration is done in the solidified-state. v

As indicatedhereinbefore; the purpose of the method and apparatus of this invention is to cold mill soap to veffectconve'rsion of thephysical properties thereof by subdivision and compacting of particles or crystals inthe mass ofthe soap to the state where they` may be said to. beinthe ultra-microcrystalline phase. Since the viscosity or hardness of the soap increases as conversion becomes more complete, it will. be apparent that the degree `of .conversion can bedetermined by measuring the viscosity of the soap.

Heretofore'the're hasbeen no wayxcf .measuring accurately the viscosity. of such. a. highly viscoussolid. material assoap. yWith the visccsity testing apparatus: shown .in Figure v20, however,` it is .possible .to .prove that the .high speed .band converter vof this invention vproduces soap of much higher-viscosityy than was'obtained by any priorc'old .milling method, .and to thus evidence the fact that .fine subdivision and. compacting `of .particles in the mass of soap has Abeen accomplished by .the apparatus.

An accurate testing procedure for .measuring the degree of conversion of soap involves measuring the timerequired to disp-lace a Apredetermined volum'ehof 'so'apiunder constant v'pressure through. a lrelativelysmall.standardized. and self-cleaning aperture'. 1

.For this .purpose the 'apparatus shown .in Figure '20 comprises apylinder-:likeydie chamber 65 having a restricted neckfat .its Atoppand closed at its'bottomby a .removable plugl. The soap to be testedV is loaded. intothe die chamber A and a plunger `ofadiameter to loosely fit the boreof. theneck .et is Aforced downwardly therethrough andy into Vthe mass of Soap 4inthe-die chamber. This is accomplished by means of `an air cylinder .60 Aconnected. .with the .plunger through a lever 'FEL' One end of the lever is connected vasat 'll/ to .the pistoriof the air cylinder, and its oppositeend is connected as at -'l2-to the plunger. Close to the plunger. end ofthe lever the latter is ksupported for. p-i'votalmotion about ahorizontal axis on a pin .13 carriedby a link 'it connected with. the frame of the `apparatus.

Thediameters of the plungerSand the restricted oricevor bore in the-neck {S6-are such that the small spacefbetvveen the-.exterior of the plunger .and the wall` of the crice preferably has a cross sectional area of approximately .0015 inch times 1.57 inches, with a length of approximately 1/2 inch for the neck .65. lThe motionfcf the plungerduring Athe test yserves to prevent clogging of this extremely small space. K l

In conducting a viscosity test the Acylinder -69 is connected with a source 0f air under Vpressure-regulatedto keep ituniform. This causes the lever l to. rock in a counterl clockwiseolirection about its pivotlsand force theplunger 68` downwardlyy throughthe-orifice inA `theneclr 56 and into the mass of soap contained in the die chamber 5. Y The plungeris allowed tontravel intothe die chamber far enough to makecertain. that'. all of the voids in-the soap-have been eliminated,l .which fact will be evidenced by a uniform new of soap upwardlythrough thespaee betweenfthe Aside of thepl'unger-a'nd the side wallvof i the bore in the neck` .66, -as seen in Figurei21. y

Assoon as the apparatus has-been placed into balanced operation'- through-achievementof an evenV ow of soap out 'ofthe' diei chamber a solen'ci'dA l5 is 'energized suchas by man'ualdepressionxof. thea'ctuatorlof a push'gbutton 'le to f effectY Vconnection-.of a`trigger ll4 4with the lever? fle. The trigger -iswiixed on a tubular member la' mounted ony theframe ofthe machine and guided for up and down reciprocatory 19... motion relative to the frame. Also slidable on the tubular member 'i8 is a supporting block 19 upon which the solenoid 15 is mounted and this supporting block is connected by means of a link' with the lever Hl so that as the arm of the lever travels upwardly the solenoid will be raised with it. It is the function of the solenoid l to releasably lock the tubular member 'i8 to the lever 10 through the link 80, and for this purpose the plunger 8| of the solenoid carries a collar 82 on its outer end, and in which the tubular member is slidably received. When the solenoid is energized, inward travel of the plunger 8| draws the side of the tubular member against the hole 83 in the block 'l5 to frictionally lock the tubular member thereto.

With the tubular member connected with the drive arm of the lever 10 in this manner the trigger il begins to rise upwardly with the tubular member and after a very short distance of upward travel it engages the actuator of a switch 82 to complete an energizing circuit to an electric clock 85, thereby starting the clock. As the plunger 68 is forced deeper into the die chamber the trigger 71 rises accordingly but at a rate which is determined by the flowability of the Vsoap through the clearance space around the plunger. After a measured distance of upward travel, the trigger engages the actuator of a second switch 86 to stop the clock so that the time it took to displace a predetermined volume of soap from the die chamber will be indicated by the clock.

The time interval so registered will be the measure of the viscosity, and comparisons can be made on the testing apparatus between soap samples of equal moisture content but varying degrees of milling.

By this means it is possible to determine the viscosity, for instance, of a conventional cold roller milled soap, and to compare with it the viscosity of soap which has been cold milled and converted by the method and apparatus of this invention. The difference in the elapsed time for the displacement of equal volumes of the two soaps will thus indicate the greater percentage of viscosity or hardness in the converted soap.

A large number of tests on soap ranging from five (5) to fifteen (15) percent moisture content has given the following index figures on relative viscosity:

Another extremely valuable characteristic of the soap which has been converted by the method and apparatus of this invention is that it has very little tendency to swell when immersed in water for any length of time. The swelling proporties or swelling coeiiicient of soap is accurately determined by pressing specimens of thesoap to be tested to the dimensions of 1/2 inch diameter by l inch long. This is done in a cylinder die under 5,000 pounds per square inch pressure. TheY compressed specimens are then submerged for 1/2 their length in water of standardized hardness which is maintained at 80 F., and allowed to remain in this condition for seventeen (17) hours. Thereafter the specimens are withdrawn for examination and measurement.

The measurement is accurately accomplished by placing the swollen samples immediately upon removal from the water upon the stage of an optical comparator so that the shadow cast by the sample can be accurately scaled.

A large number of tests gave the following degrees of swelling expressed in inches:

Moisture 5% 10% 15% Converted Sample 010 .O12 .013 Milled Soap A (Lux) l .022 Milled Soap B (Palmoliv .027 Milled Soap C (Camay)-.. .030 Floating Soap A (Ivory) .030 Floating Soap B (Swan) .020 Framed Soap .018

The narrow slit-like. space between the rimy of the wheel and the surface |22 again defines an elongated highV speed milling and compacting zone or orince, and material such as soap to be milled and converted to what may be termed the ultra-microcrystalline.phase is force fed downwardly through this space.

VSeated on and fixed to the top of the stationary milling member |23 is a frusto-conical housing EN having a hollow water cooled wall. The small diameter end of the housing is uppermost and connected with the outlet of a vertically arranged plodder to have the soap or other material to be milled force fed downwardly into the interior of the housing. The soap is fed into the housing, coaXially of the wheel E2G, and is deiiected outwardly toward the rim |2| thereof by means of a stationary conical cap |25 overlying the upper side of the wheel, so that the cap and the housing walls cooperate to direct the soap into the slit-like milling orifice between the rim of the kwheel and the surface |22 on the stationary milling member I23.- Attention is directed t0 the fact. that the walls of the housing and the cap |25 converge toward the milling orifice and at the entrance thereto, form the soap into a r relatively thin sheet prior to passage through the milling zone.

. Hence, the soap to be milled is adapted to be force fed downwardly for travel at a substantial rate through the milling zone as a Hlm-like sheet where-the rim of the wheel contacts one side thereof toexert shearing and` compacting forces thereon of such an intensity as to eifect subdi- Vision and compacting of particles throughout the mass of soap comprising the sheet. The converted soap drops freely'from the open bottom of `the milling orifice in the form of flakes to be removed by any suitable means. Y

In this case also, the soap being milled can be aerated, if desired, but since the high speed milling member never leaves the milling zone, it cannot be relied upon to carry airthereinto.` Instead, theV necessary air for aeration of the soap is brought into the upper portion of the milling zone, under pressure, by means of al series of small oriiices in the .iz'i'z'iefwal'lr of the stationary milling member communicatingwith an annular header |3| vint-he insidev ofthe member |23 and supplied with air under pressure by one or more air lines |32. -The airintroduced into the milling zone inv thismannerwill thus be occluded and nelyl dispersed inv the soap'passing through the milling zone, by thejcombined action of -the high speedmillingwheel and the congestion andv aerating grooves54f in the inner wall of the stationary milling element |23.

The wheeltype millshownwill not -have the high eiiiciency .of the previous embodiments of the invention, however, since it `requires-a running seal |21 between-theentire rim ofthe Wheel andl the undersidel of the stationary 4cap |24'. at the entrance to the milling zone. VYThis-seal may exert, to some extent,r a braking-action upon the Wheel which cannot be avoided and will limitA the speed to that at which a satisfactorylseal can be maintained.

In this case also, Athe interior'oftheannular milling member i23 lpreferably is vwatercooled, and-cooling channels |23 are provided in-the rim of the wheel to be supplied with coolant in any suitable manner.

If desired, milling can take-place vat Aopposite sides of the rim of av rotating type-conversion mill to achieve greatercapaci-ty, as seen in Figure iSd. As here-shown,vtherim `|354 is the exact counterpart of thefhigh speed millingband of the irst embodimentof theapparatus, and has concentric innerandl outer cylindrical high speed milling surfaces |36- and --|3'|, respectively, thereon'which are slightly spacedffrom complementary milling surfaces |38 and |39 on stationary innerl and outerniilling members |4ll .and I4 i respectively.

VThe lower portion of the riml is detachably joined to a ring |`42 which in yturn is connected to the hub (not shown)v ofthe wheel by spokes |43 beneath the Ainner milling member 140. The upper edge portion of the rim, linthis case, is received in a groove in an annular separator |44 similar to the separators .36 and 36' of the previous embodiments ofthe apparatus, and isfguided for rotation in said' groove.

Soap or other material to be milled is'force fed downwardly, as in the FigurelQ-embodiment, into and 'through the spaces atopposite sides of'the rim T35, and the converted-Ymaterialdischargesadjacent tothe lower. edge of the rim. To facilitate the discharge of materialfrom the inner milling space, the outer ends of the spokes are preferably blade shaped, as at 146,- so as to forcefully eject'the milled materialduring and despite `high speed 'rotation ofthe wheel.

In this case also, the stationary milling members can be provided with aerating and .congestion grooves |41 in theiropposing surfaces; and air under pressure can be introducedintothe milling spaces throughsmall orifices |48 inthe opposing walls ofthe"stationarymilling members so as to'achieve'o'cclusion .and fine' dispersion of the air inl the' soap'or otherm'ateria'l being milled by the'combined action ofthe high-sped'rim and the aerating and congestion vgrooves T41.

Another modication'of the band mill` especially suitedforsmallv scale 'applications vsuch vas a coffee grinder, consists of using a reciprocating motion'imparted to the band by a counter balanced high'speeddrive using any standard transfer m`e'chzalnism'-i'ifith 'straight line path.

'From 'the foregoing it Awill`` beV apparentthat this-invention provides a :method landapparatus 22 for coldmilling soap -(-and othermaterials) to produce a` product4 either aeratedv or deaerated, more completely converted, and `having -much greater viscosity,A or hardness,.than was'hitherto `possible-'with conventional cold .millingfapparatus, andwhereinz y 1. Animprovedroutingof.materialrbeing processed Vcarries itv across the .path of'the higl'l speed milling band to-.greatly increase lthe capacityl of the system and.l permit a `greater Iintensity .of conversion withoutY developing destructive heat;

2. The high speed milling band is substantially completely unburdenedof all that workwhich is related to the `feeding function, transporting of material through apparatus, andthe` discharginglfunctionffor removing the converted material. This removal of workfrom the high speed milling band .by providing separate feeding and discharging meansindependent. ofV the band has greatlyincreased the capacityandintens'ityin the conversion zone;

3.' The aeration 'function resulting from` gas entrainment bythe highspeed milling band has been augmented by force feeding the congestion grooves/in the walls of 'the millingslot, thereby making it possible to open the slot on the discharge side of the milling zone without losing the aerating feature of `the process. Such opening of the milling zon-e provides accessibility for the additional vuse oi' drying or cooling air blasts when desired and also -permits theV use of either a closed or open system;

4. The' removal Aof nearly all lof the iinished converted product from the milling zone before the product can be carried and swept down to the stripping knives has simplified the band cleaning or stripping function Yof vthese knives;

5. Themetered'ow and directed feed vof the input material to`both sides of the high speed milling band has made'it possible to reduce the clearance between the'sides ofthe band and the walls of the milling orflce to such a degree that the field of application has now been extended to emulsoids or'liquid and pasty materials. Also with the closer clearances possible,` the heat transfer coefcient in the intensified shearing and compacting zoneA has been'improved and enables the use `of rlow temperature coolants to refrigerate the 'material' being processed. The metered -feed also'improves'thesystem for handling powdered orgranular materials such as synthetic detergents with theirbui'ldera' very low moisture soaps, and-wheat fiour. Even abrasive powders can now be milled with a minimum of erosion of themachine partsyand 6. The-cross feed arrangement'enables the use of a considerably elongated feed and milling zone together with a guide 'means for'the milling Yband and a metering meansfcr the regulation Aof the feed of-ma-terial through thev milling zone. Consequently, the'system has a very `high throughput 'capacityY withoutv 'sacrificing the effective-- ness of extremely close' clearances lbetween' the band andthe walls ofthe` milling orifice so as to preserve'the--best` particle reduction, particlev compacting and heat removal conditions inthe milling and conversionk zone.

What we `claim as our invention is:

1. Themethod 'of milling deformable sol-id vmaterial having a crystalline phase, .to .increase the viscosity'and/ or 'hardness'of said material,y which method comprises: .apply-ing pressure upon the material vand byA said pressure continuously' forcingA thez .material in one'direction into' a space between closely adjacent parallel wall surfaces of substantial area for passage through said space and at the same time forming the material into a thin sheet of substantial area; forcing the thin sheet of material in the same direction through and from said space; and rapidly moving the parallel wall surfaces with respect to one another in a direction crosswise to that in which the material travels through the space between said parallel wall surfaces to thereby effect relative motion between the surface layers of the sheet of material in said space, throughout the entire area thereof.

2. The method of milling deformable solid material having a crystalline phase, to increase the viscosity and/or hardness of said material, which method comprises: applying pressure upon the material and by said pressure continuously forcing the material in one direction into a space between closely adjacent parallel wall surfaces of substantial area for passage through said space and at the same time forming the material into a thin sheet of substantial area; forcing the thin sheet of material in the same direction through and from said space; rapidly moving the parallel wall surfaces with respect to one another in a direction crosswise to that in which the material travels through the space between said parallel wall surfaces to thereby effect relative motion between the surface layers of the sheet of material in said space, throughout the entire area thereof; and abstracting heat from the material passing through said space to prevent a temperature rise therein above the crystallinereversion point of the material.

3. The method of milling and aerating viscous material, which comprises: force feeding the Inaterial through a slit-like extrusion orifice having its discharge end open to the atmosphere and which defines a shearing and compacting zone, to form the material into a film-like sheet in said zone; imparting motion to the surface layer of material at one side of the sheet crosswise of the travel of the sheet through said zone relative to but substantially parallel with the surface layer of material at the opposite side of the sheet, and high speed internal churning motion to the mass of the material comprising said sheet, so as to effect subdivision and compacting of particles throughout the mass of the material comprising said sheet; and introducing a gas into said shearing and compacting Zone for occlusion and fine dispersion of the gas in the material by the churning thereof along with the shearing and compacting forces acting upon the material.

4. The method of milling viscous material to refine and aerate the same, which comprises: moving a mass of deaerated material to be milled and aerated through a feeding zone toward a shearing and compacting zone; forming the material leaving said feeding zone into a lm-like sheet; force feeding said sheet edgewise through the shearing and compacting zone; bringing a thin fllm'of air into contact with the surface layer of material at one side of the sheet in said zone; and imparting high speed motion to said surface layer of material in the shearing and compacting zone relative to but substantially parallel with the surface layer of material at the opposite side Yof the sheet, crosswise of the travel of the sheet through said zone, and high speed internal churning motion to the mass of the material comprising said sheet, so as to effect subdivision and compacting of particles throughtout the mass offmaterial comprising said sheet 24 and occlusion and line dispersion of the air in the material by the churning thereof along with the shearing and compacting forces acting on said material.

5. The method of milling and aerating viscous material, which comprises: forming the material into the shape of a film-like sheet; force feeding a plurality of such sheets edgewise in one direction through a shearing and compacting zone with the sheets in side-by-side parallel relationship; introducing air into said zone; and in said zone imparting high speed motion to the surface layers of material at the inner sides of the sheets relative to and substantially parallel with the surface layers of material at the outer sides of the sheets, crosswise of said feed direction, and simultaneously effecting high speed internal churning of the mass of material comprising each of said sheets so as to effect subdividing and compacting of particles throughout the mass of material comprising each sheet, and occlusion and fine dispersion of air throughout the mass of material comprising the sheets.

6. The method of milling deformable solid material, which comprises: forcibly moving the material to be milled along a predetermined path toward and through a slit-like orifice defining a shearing and compacting zone which is relatively short in the direction of travel of the material; gradually conforming the mass to the shape of said orice as the material travels along said path; utilizing the force required to move and shape said mass to cause rapid travel of the material through said orifice; and by a separate force imparting motion to the surface layer of material at one side of the lm thereof in said orifice, relative to the surface layer of material at the opposite side of the film, in a direction substantially crosswise of the direction in which the material travels through said orifice, and at a speed great enough to effect shearing and compacting of particles in the mass of the material travelling through said orifice.

7. In the method of milling a deformable solid material, the steps of: applying pressure upon the material and by said pressure eXtruding the material through the narrow dimension of an elongated narrow orifice into a zone having opposite sides of substantial area; and passing a shearing member with opposite faces of substantial area through the material in said zone, centrally thereof, in the direction of the long dirnension of said orifice with the opposite faces of said shearing member closely adjacent and parallel to the opposite sides of the said Zone and at a high speed sor that the combined action of the shearing member and the sides of the zone on the material as it passes through the orifice and through said zone produces intense shearing and compacting forces in the mass of the material to thereby finely mill the same.

8. The method of milling highly viscous solid material, which comprises: forming the material into a sheet not greater than about .015 of an inch in thickness; force feeding said sheet edgewise in one direction, at a rate of at least 200 feet' per minute through a slit-like extrusion orice defining a conversion zone having a length of atleast l inch `in the direction of travel of the sheet; and as the sheet travels through said zone, imparting motion at a rate of at least 1,000 feet per minute to thesurface layer of material at one side of the sheet relative to the surface layer 0f material at the opposite side of the sheet, crosswise of the direction of travel of the sheet through 'sai'dzona' to 'effect' shearing and compacting of particles 'in' the material' throughout the thickness 'of the sheet.

9.1 The "method of milling i and 'aerating highly viscous 'solid Ymaterial which comprises: forming the material' into a'sheet' not greater than 'about .015 of 'anv inch in" thickness; 'force feeding said sheetV edgevvise'in one direction, at a rate of at least 200feet per minute,v through' a slit-like extrusion orice defining a conversion zone; as the sheet'travels through said zone, imparting motion at a rate of' at least 1,000 feet per minute to the surface 'layer of material' at one side of the sheet relative to `the'surface layer'of'material at the opposite side of the sheet, crossvvise of the direction of travel ofthe sheet through said zone,'vvhile-violently churning the material internally so as to effect 'shearing'and compacting of particles in'the material throughout' the thickness 'ofthe sheet; and introducing 'air into said conversion zone for' occlusion and' fine dispersion ofthe air in said material by the 'churning thereof' along with the shearing andcompacting forces exterted on the' material passing through said zone.

10. The method of milling deformable solid material, which'comprisesr moving a mass of the material'to be milled toward'a slit-like extrusion orifice 'defining a 'shearing andcompacting zone;

dividing the mass of material' approaching 'said I zone into separate relatively thin sheets; rapidly feeding said sheets in spaced apart side-by-side opposing relationship edgewise through said orice'with the surface 'layers'of materialat the outer sides of the sheets in intimate contact with the sides of the orifice, and-in 'a direction cross- Wise of the length of said'orice';' and in said orifice; imparting high speed motion simultaneously to the surface layers of material at the inner 'opposing 'sides 'of 'said' sheets, lengthwise of said orifice, so that the'combined effect of such motion and the inertia of the Amass'of the material causes subdividing and compacting of particles in the 'mass of bothsheets.

l1. The-'method of cold milling highly viscous solid material, Which comprises: forming the material'in'to a film-like'sheet; rapidly feeding said sheetedgewise 'in one' direction vthrough a conversion zone; and imparting extremely'high speed motion' tothe entire surface layer of material at one side of 'the sheet'in said Zone as the sheet passes therethrough, crossvvise of said feed direction, While utilizingI the inertia of the mass of material comprising said sheet' to vresist such motion' so as4 to effect extremely high relative motionv between the surface 'layers of lmaterial at thev opposite sides of the sheet" and thus produce iine subdivision and compacting of particles inthe mass of material' comprising said sheet.

12.* The'znethod of"milling deformable solid material, which comprises form-ing the material to be milled into a 'film-like sheet; force feeding said'sheet in one direction througha shearing and compacting zone in which the sheet is constrained to edgewise travel; imparting high speed motion' to the' surface layer -of material at one side` of the sheet' as it travels through said zone, crosswise of said feed direction,irelative to but substantially"parallel-Withthe surface layer of material at the oppositeside of the sheet; and congesting the material adjacentto said opposite side 'of 'the-sheet at spaced areas-thereof inthe shearing and' compacting zoneso that the combined' action of' suchvcongestion and the high .speed 'motion .'ofsaid ysurface layer of material 26 effects 'subdividing and" compacting'of vparticles inthe mass'of material comprising said film.

13. The method of milling viscous-material to refine and 'aerate' the same, which comprises: moving aV mass 'ofthe material to 4be milled through a'feedi'n'g zene toward a 'slit-like extrusion orifice 'deiiing' a shearingy and compacting zone; force feeding thematerial-leaving said feeding zone inone direction'through said shearing and lcompacti'rigzone toformthe material int-o a film-like shee't;" bringing a lthin lm of air into contact'with the. surface layer of' material at one side-ofJthe-sheet' passing throughv said zone; impartinghigh'speed motionto said surface layer of material as the sheetmoves through the shearing and compactingrzone, crosswise of said feed direction, relative tobut substantially parallel with the surfacev layer ofmaterial at the opposite side of the sheeti and congesting the material adjacent to lsaid vopposite side of the sheetY at spaced areas thereof in said shearing and compacting zone, so that the combined action of such congestin and the high speed motion of said surface'layerof 'material produces subdividing andcompacting of particles in' the mass of material comprising said sheet, andthe occlusion'and'ne'dispersion therein of the air brought into contact 'with said- 'first designated surface 'layer of materiali' 14. The method of' mi1lin`g"visc'o`us material to refine' and aerate'tlie' sama `which comprises: forcing the vmaterial' to be -milled and aerated through a' slit-likeextrusion orifice having its discharge end open tothe atmosphere, and which orifice' defines a shearing and compacting zone, to form'the materia1l`into a film-like sheet in said'zone; imparting high-speedmotion to the surface' layer of materialat one side of the sheet as it moves through said zone -relative to but substantially parallelwith'the surface layer of material at` the 'opposite side of the sheet, While simultaneously vi'ol'e'ntl'y" churning the material internally so'as to effect-subdividing and compacting'ofparticles" throughout the mass -of the material'comprising said sheet; and introducing a gas 'into said shearing and rcornpactingzone for occlusion and fine dispersion of the -gas in the' material by .the 'churning thereof along with the' shearing and 'compacting forces acting upon the material.' y

15. Milling apparatus, comprising: amovable milli'ngelernentv constrained to travel in one direction'alon'g'a predetermined path and having an elongated YAmilling surface thereon of substantial'area; a stationary-milling element having an 'elongated comple'rnentary milling surface thereon of'substantial area in juxtaposition to but spaced slightly'ffromsaid surface Vonthe movable milling element'fmeans'for driving said movable: milling relement at high speed; stationary guide means' for directing material-to be milled 'ina direction'crosswise of the path-travelled by the milling surface on 'the-movable millingelement; and'into the "space between lsaid surfaces on the stationary and movable elements and feed' means communicated with said guide means for' forcingmaterial to be ymilled under substantial pressure into -said' -guide means Vand across the space between 'said-surfaces on-the stationary and movable milling elements.4 l

16.` The apparatus set forth in claim 15 further characterized 'byv 'fthe fact" that said stationary miling element`hasaseris ofspaced apart congestion groov'esth'ereinlopening .to and extending across said milling surfacethereom through 27 which material passes as it is forced through the space between the stationary and movable milling surfaces.

17. Milling apparatus comprising: an elongated movable milling element having opposite sides providing movable milling surfaces of substantial area; means mounting and constraining the movable milling element to movement along a dened path which extends lengthwise of said element; stationary milling elements at opposite sides of the path of the movable milling element having opposite walls providing stationary milling surfaces of substantial area overlying said opposite sides of the movable milling element with a milling. clearance therebetween; means for forcibly feeding material to be milled into the milling clearances between the stationary andmovable milling elements simultaneously along the entire length thereof for passage through said milling clearances in a direction vcrosswise to the path of the movable milling element; and means for imparting high speed motion to said milling element.

18. Milling apparatus, comprising: a pair of pulleys rotatable about ixed spaced apart parallel axes; an endless fiat band trained over said pulleys to be driven at high speed thereby. with one stretch of the band travelling in a straight path between said pulleys, said band having opposite at sides defining milling surfaces; an

elongated wall at each side of said band having a milling surface facing one flat side of the band and extending lengthwise thereof; means mounting said walls in fixed relation to the pulley axes with said surfaces thereof close to but spaced slightly from the sides of the band, said wall surfaces defining a slit-like shearing and compacting zone therebetween of substantial length measured in the direction of band travel therethrough but relatively short in a direction cross- L wise of band travel; means for feeding material to be milled through said zone, crosswise of the length thereof; and means on said walls near the ends thereof providing seals embracing the band to prevent the material being milled from passing out of the opposite ends of said shearing and compacting zone.

19. Milling apparatus, comprising: a pair of walls each having an elongated milling surface thereon of substantial area; means mounting said walls in xed. spaced apart relationship with said milling surfaces thereof opposite and relatively close to one another, said milling surfaces defining the sides of a slit-like extrusion orifice of substantial length but relatively short in a direction crosswise of said surfaces; an elongated movable milling element having opposite sides defining milling surfaces of substantial area and having a thickness slightly less than the spacing between the milling surfaces defining the sides f the slit-like extrusion orifice; means constraining said movable milling element to travel lengthwise through said extrusion orice with the opposite sides of the movable element spaced slightly from the surfaces dening the sides of said orifice; means xed with relation to said walls defining a feed nozzle opening to said extrusion orifice along the entire length thereof adjacent to one side edge of said movable milling element, through which material to be milled is adapted to be forced for travel through said extrusion orifice crosswise of the long dimension thereof; and means for imparting high speed motion to said movable milling element.

20. Milling apparatus, comprising: a pair of walls each having an elongated straight milling surface thereon of substantial area; means mounting said walls in fixed spaced apart relation with said milling surfaces thereof opposite and relatively close to one another, said surfaces dening the sides of a straight slit-like extrusion orice of substantial length but relatively short in a direction crosswise of said surfaces; an endless milling band having opposite sides providing milling surfaces of substantial area and having a, thickness slightly less than the spacing between said surfaces which denne the sides of the slitlike extrusion orifice; means constraining said band to travel lengthwise through said extrusion orifice with the opposite sides of the band spaced slightly from the milling surfaces defining the sides of said orifice; means at the opposite ends of said walls defining pressure seals closely embracing said band; means fixed with relation to said walls providing a feed nozzle opening to said extrusion orifice along the entire length thereof between said seals and adjacent to one side edge of the band, through which material to be milled is adapted to be forced for travel through said extrusion orifice crosswise of its long dimension; and means for driving said band at high speed.

21. The milling apparatus set forth in claim 20 further characterized by the provision of means for forcingmaterial to be milled through said extrusion nozzle and` consequently through said slit-like extrusion orifice.

22. The milling apparatus set forth in claim 21 wherein said means for forcing material to be milled through the feed nozzle comprises a screw rotatable inside the feed nozzle.

23. The milling apparatus set forth in claim i9 further characterized by the provision of separator means fixed with relation to the feed nozzle and extending along the entire length of the extrusion orice adjacent to the discharge opening in the feed nozzle for directing material to be milled to the opposite sides of the movable milling element and for metering the iiow of material into said extrusion orifice.

24. The milling apparatus set forth in claim 23 further characterized by the provision of a series of relatively small teeth extending from the opposite sides of said separator means and spaced apart along the entire length thereof for effecting shredding of the material prior to entrance thereof into said milling orifice.

25. Milling apparatus, comprising: an elongated feed nozzle having a discharge opening in its side extending substantially the entire length vof the nozzle; stationary milling means fixed to said side of the feed nozzle and having elongated spaced apart opposing walls the surfaces of which define a slit-like extrusion orifice extending the full length of said discharge opening in the nozzle and in open communication therewith, so that material discharging from the feed nozzle travels through said orifice crosswise of the long dimension thereof; an endless metal movable milling band guided for lengthwise travel through said orifice, said band having a thickness slightly less than the spacing between the surfaces dening the sides of the extrusion orifice so that material forced through the orifice will be brought into intimate contact with the sides thereof and with the opposite sides of the band; means for driving the band at high speed to eect shearing and compacting of particles in the mass of material passing through the milling orifice; means fixed with relation to said walls providing an elongated chamber at the outlet side of said 

